JP2014509950A - Mandrel transfer device for tube rolling mill - Google Patents

Abstract

  A rolling plant (R) for pipe rolling having a multi-stand rolling mill (5) with two or more rolls for carrying out the speed-controlled mandrel rolling process is arranged in the inlet area of the rolling mill (5) and is placed on a mandrel ( 31) The unlocking device (61) cooperating with the rear tongue and the mandrel (31) in an adjusted state with the first unlocking device (61) arranged in the exit area of the rolling mill (5) An unlocking device (71) cooperating with the front tongue.

Description

  The present invention relates to a mandrel transfer device for a multi-stand continuous tube mill operating with a mandrel.

  Prior art longitudinal multi-stand mills operating with a mandrel have traditionally been classified into various types according to the structure relating to rolling speed control and mandrel speed and position in the tube.

  Continuously floating (that is, free) mandrel mills allow the mandrel to move freely inside the tube while the mandrel passes through the multi-stand mill due to the friction generated between the mandrel and the inner wall of the tube. It is. The mandrel gradually accelerates as the rolling stands are sequentially engaged. The mandrel is removed from the tube when the free mandrel assumes the same forward speed as the tube at the end of the rolling cycle leaving the rolling line, or in all cases when the end of the tube exits the final rolling stand. In this type of rolling mill, very high productivity of 4 to 5 pieces per minute is obtained with a short cycle time.

  On the other hand, this type of rolling mill has various drawbacks. The tube located between the rolls is overfilled in the first stand and underfilled in the finishing stand at the end of the mill, so the mandrel acceleration is not convenient for dimensional quality and tube failure Causes a condition. Therefore, there are problems of rolling stability and excessive tolerance of products. In addition, the tube head, where the mandrel no longer reaches, remains hot for a long time immediately after the first rolling step, while the rear part where the mandrel is still inserted during the rolling process The tube cooling is not uniform over the entire length of the tube because it is partially cooled by the mandrel itself in contact. In these rolling mills, it is usually necessary to provide a downstream heating furnace to make the tube temperature uniform before final rolling to calibrate or further reduce the tube diameter.

  A second type of mill is known as a partially floating mandrel mill where the mandrels are held during rolling and move slower than the tube at a technically convenient speed. At the end of the rolling operation, after the end of the tube leaves the final rolling stand, the mandrel is released from the holding device while the mandrel remains in the tube itself and subsequently leaves the rolling line Is done. When the end of the tube exits the final rolling stand, and therefore when the free mandrel has taken the same forward speed as the tube, the mandrel is removed from the tube leaving the rolling line. Short cycle times and consequently high production rates, for example 3-4 tubes per minute, are obtained with this type of rolling mill. On the other hand, in terms of the non-uniform temperature along the tube, the same drawbacks as in the previous type of rolling mill are seen.

  A third type of rolling mill is called a holding mandrel rolling mill and features a rack and pinion type mandrel holding device. At the end of the tube rolling operation, when the end of the tube leaves the final stand of the rolling mill, the leading end of the tube is already pre-fitted downstream of the rolling mill by a drawing device that holds the outer surface of the tube. The drawing device, which is generally provided in the form of a specific rolling roll stand, pulls the tube forward in the same rolling direction, while a holding system secures the mandrel and moves it inside the tube, which is the inlet side of the rolling mill. Is pulled back and removed from here in a conventional mandrel transfer cycle and reintroduced. The drawing device or drawing machine also has a function of reducing the outer diameter of the tube by further rolling the tube, and does not include a mandrel inside the tube. This type of rolling mill has a long cycle time, so the productivity is lower than the above type, and generally two tubes per minute can be rolled.

  In conventional rolling in a holding mandrel plant, the mandrel advances during the rolling step at a controlled speed, also called holding speed, in the same direction of motion as the tube from the inlet to the outlet of the multi-stand mill throughout the rolling cycle.

  In a rolling process carried out using this type of rolling plant, a mandrel is inserted into the drilling cell at the beginning of each rolling cycle starting from the end in the direction of the tip of the drilling shell itself, with the same movement in the direction of the tube rolling. It is normal to be done.

  This initial operation may be performed in alignment with the rolling axis, which is known as alignment insertion or out-of-line, but in this case known as pre-insertion and rolling by reducing the travel distance of the mandrel holding device. Pre-insertion of mandrels into the perforated shell is used to shorten the cycle time of the machine itself and increase productivity. Therefore, limiting this technique is its low productivity, especially for rolling mills used for rolling small or medium-sized tubes, for example tubes having a nominal diameter shorter than or equal to 7 ″ (177.8 mm). .

  Another type of rolling mill is called a holding mandrel type that includes a drawing device and releases the pipe at the end of rolling, and the mandrel passes through the drawing device. The rolling process performed with this type of rolling mill is that the mandrel is fixed to a specific holding device at the end of the tube rolling operation, whereas the tube is pulled from the mandrel by a drawing device by pulling along the rolling line. Removed. After the entire tube has passed through the drawing device, the mandrel is then released from the holding device, transported forward by a press roll along the rolling line, passes through the drawing device immediately after the tube, and finally the drawing device itself. It is taken downstream and passes through a circuit provided for mandrel reuse. These mills provide a relatively short cycle time of 2.5 tubes per minute.

  The disadvantage of the latter type of plant is that the process involves transferring still hot mandrels by press rolls, with the risk of damaging the mandrel surface. In this type of process, the mandrel holding device during the rolling step, usually of the rack type, must include a release device suitable for releasing the mandrel itself after it has been cycled to remove the tube. In order to carry out the rolling process in a rolling plant with a holding mandrel, the passage of the mandrel in the drawing device can open and close rapidly, assuming that the drilling shell, the tube and the mandrel move at high speed in the rolling line. In each rolling cycle, it is necessary that the drawing apparatus is provided with a stand through which the rolling tube is first passed and then the mandrel. If the operational accuracy of the drawing device is not guaranteed, there is a risk of misalignment of the edges of two adjacent rolls and the resulting longitudinal marking of the rolled tube.

  The process with a holding mandrel type rolling plant is advantageous in all cases in terms of the tube quality that can be obtained and the thermal conditions at which the tube exits the mill. Indeed, with this type of rolling mill alone, it is possible to include calibration of the final diameter of the tube, again without intermediate heating.

  To ensure an efficient rolling process with either a holding mandrel or a partially floating mandrel type, a mandrel holding device that ensures mandrel speed stability during the rolling cycle, is robust, and can lock and release the mandrel itself. It is important to use and this possibility is not provided by chain sprocket systems, the latter being very common today. In fact, in the case of rolling plants with partially floating or holding mandrels, the holding device with the chain wrapped around the sprocket and equipped with a locking carrier is due to premature wear of the parts, noise, and the elongation that the chain undergoes over time, It is inconvenient. In order to avoid such drawbacks of the chain system, some known plants of the speed controlled holding mandrel type use an in-cycle unlocking system to carry out rolling methods with short cycle times. In all cases, these systems do not function in the centered state around the mandrel traction axis, adding the problems associated with flex loads acting on the unlocking system.

  A rolling mill and its holding mandrel rolling process are disclosed in US Pat. No. 6,057,056, wherein after the tube is pulled out while the mandrel is still held, the tube is transferred while the mandrel is no longer inside, and the drawing device After being rolled, the mandrel is discharged from the rolling line downstream of the rolling mill and laterally to the rolling line.

  However, in the known holding mandrel plant described above, it is difficult to manufacture a short tube because the tube is shorter than the distance between the shaft of the final stand of the multi-stand rolling mill and the first stand of the drawing device.

  The market allows for a high degree of flexibility in the final product, which means that different lengths of tube can be rolled by exchanging a minimum number of plant parts, reducing the tube rolling cycle time and overall plant productivity. There is a need for a rolling plant that can increase the quality of the finished tube, at least without compromising it, and the plant itself can have a more rational structure and reduce the manufacturing and management costs of the plant.

International Publication No. 2011/000819 Specification

  The main object of the present invention is to produce a mandrel transfer device for a tube rolling plant with a continuous multi-stand mill working with a mandrel, which is cost-effective to manufacture and operate and ensures high productivity of the rolling process. It is.

  A further object of the invention is for a holding mandrel or semi-floating mandrel type tube rolling plant that allows precise control of the mandrel speed during the rolling operation and functions in a centered state with respect to the traction force applied to the mandrel by the tube being rolled. To manufacture a mandrel transfer device.

  According to the first aspect of the invention, the rack device and the unlocking device for locking and releasing the tongue portion of the mandrel, the two racks juxtaposed in parallel to the rolling axis are provided. A mandrel defining a rolling axis, the rack device having two racks each having two teeth and two ends, and an unlocking device being disposed at one end of the two racks These objectives are achieved by a mandrel transfer device for a multi-stand tube rolling mill comprising:

  The mandrel transfer device of the present invention is suitable for all holding or semi-floating mandrel type rolling plants of the type described above. The mandrel transfer device allows the mandrel used in each rolling cycle to be inserted into the piercing shell on the line, but contrary to what is normally performed on a holding mandrel mill, that is, in the direction opposite to the rolling direction, It is particularly suitable and advantageous for a speed-controlled holding mandrel tube rolling plant in which a multi-product rolling mill is carried out backwards and a high-productivity rolling process is carried out, which first enters the end of the rolling mill from the end.

This configuration provides additional advantages because it is possible to omit the drawing device or machine from the rolling plant while maintaining the advantage of using a well-known type of holding mandrel rolling process.
A further advantage of the plant of the present invention is that it can roll tubes of various lengths, especially tubes that are shorter than well produced tubes that are longer than approximately 8-10 m at the exit of a multi-stand mill.
The advantage derived from not using a drawing machine at the end of the rolling line is that a tube with thinner walls is obtained. In fact, when a holding mandrel mill is provided with a drawing machine, the prior art usually reduces the possibility of rolling a thin tube with a high diameter to thickness ratio. This usually means that the drawing machine performs a further rolling function to reduce the outer diameter of the tube by 3% to 5% in the absence of a mandrel inside, and this action results in a tube wall thickness of 1.5%. Due to the fact that it will increase by 2.5% to 2.5%. Essentially, a reduction in the ratio of tube outer diameter to tube thickness in an amount equal to 4.5% to 7.5% is seen. This is avoided by the rolling plant of the present invention.

  The advantages of this type of rolling mill can be exploited if the mandrel transfer device is optimal for carrying out the holding mandrel rolling process. For example, by using the plant described above, intermediate between the mandrel rolling stage and the final diameter reduction stage normally performed in a calibration or stretcher type rolling mill in prior art holding mandrel rolling mills. It is possible to reduce the final diameter of the tube to avoid heating.

  In summary, in the optimal but not limited use of the mandrel transfer device of the present invention, the rolling process is performed in a rolling plant after the mandrel used in a particular rolling cycle is loaded in the downstream area of the mill. It needs to be inserted backwards into the multi-stand mill by a mandrel conveyor, which is a conveyor located downstream of the multi-stand mill. The perforated shell to be rolled in this cycle by a particular mandrel is loaded by translating it transversely to the rolling direction and placing it on the rolling axis at the multi-stand mill entrance. The mandrel insertion exits the first stand of the multi-stand mill and continues backwards into the drilled shell, and finally at the moment when the end area of the mandrel emerges from the end of the drilled shell, Is locked to a mandrel conveyor disposed on the inlet side of the multi-stand mill. In order to enable locking by the mandrel conveyor, the rear end of the mandrel is provided with a specific tongue for locking. In this respect, the mandrel of the rolling cycle is arranged according to the characteristics of the drilled shell used and the tube to be produced. Subsequently, while the mandrel advances backward at the controlled rolling speed, the perforated shell is pushed into the multi-stand rolling mill by the automated feed roll.

  The control system (of a well-known type) of the rolling plant allows the final part of the pipe (ie the end or the rear part) to be the final stand where the wall thickness is rolled when the mandrel tip is immediately upstream of the stand itself. Rolling, thereby avoiding using the next drawing machine to remove the rolled tube from the mandrel. Such a point is conventionally known as a meeting point between the mandrel and the rolled tube.

  Subsequently, also during the same rolling cycle, the tube moves towards the outlet of the multi-stand mill while the mandrel advances its movement again in the direction opposite to the rolling direction towards the mill entry area. The insertion movement of the mandrel inside the perforated shell and the relative movement between the mandrel and the tube reduces the time over which the already rolled tube is superimposed on the mandrel held in the inner cavity. In this way, cooling of the tube itself caused by contact with the mandrel body at a lower temperature than the tube is suppressed, thus facilitating the next rolling by reducing the outer diameter without necessarily performing intermediate heating.

  When the mandrel is withdrawn from the inside of the tube, the tube stops downstream of the multi-stand mill at a position completely away from the installation range of the rolling mill, whereas the mandrel used in this rolling cycle is It stops at the entrance area of the rolling mill itself at a position where the tip is completely outside the rolling stand and is completely free from the installation range of the rolling mill.

  In this respect, on the inlet side, the mandrel used in the rolling cycle that has just ended is discharged from the side of the rolling shaft to the off-line position away from the rolling shaft. A predetermined rolling cycle is thus completed and at the same time or immediately after, the next drilling shell is loaded from the outside of the line onto the rolling shaft and the next rolling cycle, which is carried out in the same order, is started.

  The discharge operation of the mandrel from the line at the entrance area and the insertion of the next drilled shell on the line are carried out in various ways, for example by using two rotating arms operating in harmony with each other. It is good to be done. On the exit side of the multi-stand mill, the tube rolled in the just completed rolling cycle is in a fixable position and is reached after braking performed by a known type of braking means, and by various systems, For example, it is discharged from the rolling shaft to a position outside the line by a rotating arm. The mandrel to be used for rolling in the next cycle is also inserted into the rolling shaft from an off-line position, for example by means of a rotating arm. In order to shorten the cycle time, the movements of these two rotating arms are coordinated.

  In this cycle, as with all previous cycles of the process, a new mandrel is inserted backwards in a rolling mill that reproduces all stages of the work already described for the previous cycle.

  The quick, accurate and harmonious execution of the mandrel unlocking operation in each rolling cycle in an optimal way is the unlocking included in the two mandrel transfer devices in each of the inlet and outlet areas of the rolling mill Guaranteed by the specific features of the device.

-Using the mandrel transfer device of the present invention in a holding or semi-floating mandrel rolling plant ensures high productivity of the rolling plant due to the execution speed of the unlocking operation. In addition, in known types of rolling plants, the vertical operation of the mandrel / drilling shell support roll is usually provided to provide room for the rack tip having an installation range below the rolling axis X which interferes with the mandrel / drilling shell support roll. Use of the system is avoided.

  The dependent claims refer to preferred embodiments of the invention.

1 schematically shows a plan view of a line portion of a pipe rolling plant of the present invention at a defined stage of any cycle of the pipe rolling process. Fig. 2 schematically shows a plan view of the parts of the plant of Fig. 1; Fig. 3 schematically shows a side view of the component of Fig. 2; Figure 3 shows an enlarged side view of the details of the part of Figure 2; Fig. 5 shows a top view of the details of Fig. 4; FIG. 6 shows a detailed front view of FIG. 5. FIG. 6 shows a cross-sectional view taken along the plane AA of FIG. 5 in detail. FIG. 6 shows a cross-sectional view along the plane AA of the detail of FIG. 5 in different operating positions. Fig. 2 schematically shows a plan view of another part of the plant of Fig. 1; FIG. 10 schematically shows a plan view of a variation of the component of FIG. 9. Fig. 10 schematically shows a side view of the component of Fig. 9; Fig. 10 shows an enlarged side view of the details of the component of Fig. 9; FIG. 12 shows a top view of the details of FIG. FIG. 13 shows a detailed front view of FIG. 12. FIG. 13 is a cross-sectional view taken along the plane AA of FIG. 12 in detail. FIG. 13 shows a cross-sectional view along the plane AA of the detail of FIG. 12 in different operating positions. FIG. 3 shows a front view of an enlarged portion of the component of FIG. 2. FIG. 10 shows a front view of an enlarged portion of the component of FIG. 9. Fig. 9b schematically shows an enlarged side view of the component of Fig. 9a. FIG. 19 shows a top view of the details of FIG. FIG. 20 shows a detailed front view of FIG. 19. FIG. 20 is a cross-sectional view taken along plane AA of FIG. 19 in detail. FIG. 20 shows a cross-sectional view along the plane AA of the detail of FIG. 19 in different operating positions.

Additional features and advantages of the present invention will be apparent in light of the detailed description of the preferred but not limited embodiments of the pipe rolling plant according to the present invention illustrated by way of non-limiting example with reference to the accompanying drawings. Will be.
Equal reference numerals in the various figures correspond to the same elements or parts.

  The figure shows a rolling plant according to the invention, indicated generally by the reference R, operating in conjunction with a speed control mandrel to carry out a continuous speed control high productivity mandrel tube rolling process with the transfer device of the invention. A preferred embodiment is shown. The rolling plant R defines a rolling axis X and a rolling direction 23 followed by a rolling material, generally referred to as a piercing shell 39, and a rolled tube 42. The plant R conventionally has an inlet area or inlet side 20 provided with a mandrel take-out device 2 for taking out a mandrel from the rolling shaft X and a drilling shell loading device 1 for loading the drilling shell into the rolling shaft X, and multi-stand rolling. It is divided into a rolling area 21 in the strict sense in which the machine 5 is provided, and an outlet area or outlet side 22 in which the mandrel loading device 4 and the rolling tube take-out device 3 from the rolling axis X are provided.

  The loading device 1 for the perforated shell 39 along the rolling axis X is preferably arranged in the form of a rotary arm that is disposed at the entrance of the multi-stand rolling mill 5 and is mounted on the side of the rolling axis X, but is not limited thereto. Absent. In operation, such a perforated shell loading device 1 picks up the perforated shell 39 from a lateral position away from the rolling line, as is well known in the prior art, although not shown in detail in the drawing, This is placed along the rolling axis X on which the supporting rolls are arranged.

  The take-out device 2 for the mandrel 31 from the rolling axis X is also preferably arranged in the form of a rotating arm that is disposed at the entrance of the multi-stand rolling mill 5 and is mounted on the side of the rolling axis X, but is not limited thereto. The take-out device 2 of the mandrel 31 is attached to the entrance of the multi-stand rolling mill 5 on the side opposite to the piercing shell loading device 1 with respect to the rolling axis X.

  In operation, the apparatus 2 picks up the mandrel 31 used to roll the tube 42 from the rolling axis X itself at the end of each rolling cycle and carries it to a lateral position away from the rolling line. This position includes the cooling of the mandrel, which has risen in temperature due to the action of heat received from the tube during the rolling cycle, and the lubrication prior to being transferred to the exit side 22 of the mill for subsequent use in other rolling cycles. Belongs to a mandrel recirculation device used in a process involving a method not shown in detail in the figures for well-known purposes.

  The take-out device 3 for the rolling tube 42 from the rolling axis X is preferably arranged in the form of a rotary arm that is arranged at the outlet of the multi-stand rolling mill 5 and is attached to the side of the rolling axis X. At the end of the process, the pipe 42 is taken up and transferred to a lateral position away from the rolling axis itself for storage or other processes or operations. The take-out device 3 from the rolling shaft X is mounted on the outlet of the multi-stand rolling mill on the same side as the perforated shell loading device 1 shown in the lower part of FIG.

  The mandrel loading device 4 along the rolling axis X may be disposed at the outlet of the multi-stand rolling mill 5 and provided in the form of a rotating arm on the side of the rolling axis X, but is not limited thereto. In operation, the device 4 picks up the mandrel 31 from a position outside the lateral line and supports the rolls, where the mandrels and tubes belonging to the mandrel conveyor 7 on the outlet side 22 are arranged (not shown in detail for the prior art). This is placed along the rolling axis X. On the same side as the mandrel take-out device 2 shown in the upper part of FIG. 1 with respect to the rolling axis X, the mandrel loading device 4 is mounted at the outlet of the multi-stand rolling mill 5.

  As an alternating stand type rolling mill in which the stands are arranged in order so that the roll gap of the odd stands along the rolling axis X corresponds to the groove bottom of the even stands or vice versa, and two or more rolls are provided per stand The multi-stand rolling mill 5 may be used, but is not limited thereto. The rolling plant of the present invention may have other types of pipe rolling mills without departing from the spirit of the invention.

  The mandrel conveyor 6 on the inlet side 20 is a longitudinal mandrel working part having a mandrel support device with an adjustable height roll 92 and two racks 62 ', 62 "(not shown in FIG. 1) parallel to each other. 62. Three parts 62 ', 62 ", 62" "are robust between the distal end of the gripping area of the mandrel 31 and the two racks 62', 62" of a predetermined length. A rigid connection 62 "" is provided between two parallel racks so as to form a simple body. Each rack 62 ', 62 "has a balanced respective arrangement above and below the rolling axis X. Tooth portions 51, 51 'and 52, 52'. Thus, the four tooth portions 51, 51'52, 52 'are arranged symmetrically with respect to the axis of the mandrel 31 coinciding with the rolling axis X, so that the axial load generated by the work related to rolling acting on the mandrel is reduced. The four tooth portions and the pinions 55, 55 ', 56, and 56' fitted therewith are uniformly reduced. The small structure inherent to part 62 allows very high axial loads to be applied to the mandrel without risk of bending during rolling.

  The pinions 55, 55 ′, 56, 56 ′ which apply the necessary force and transmit the movement to the part 62 are constituted by a shaft support structure provided with gears and are arranged symmetrically with respect to the rolling axis X. The gears of the pinions 55, 55 ', 56, and 56' are preferably mounted on the top and bottom of the rack itself. Thus, the gears of the pinions 55, 55 'fitted with the two teeth of the rack 62' are kinematic from the gears of the pinions 56, 56 'fitted with the two teeth 52, 52' of the rack 62 ". It is good to be separated.

  The pinions 55, 55 ', 56, 56' are connected in a known manner to respective drive devices 58 having one or two speed reducers and a number of motors corresponding to the number of gears of the pinion box. . All the shafts coming out of the pinion box 57 should be facing the same side, and all the motors should be on the same side with respect to the rolling shaft 23.

  Each of the two racks 62 ′, 62 ″ has two inner gears 53 ′, 54 ′ and two outer gears 53, 54 in a space where the rigid connection 62 ″ ″ is not provided. In the mandrel holder head areas 68, 69 and the rear area of the system 62, the gears 59 ', 59 "are mounted only outside the two heads 68, 69. The gears 59', 59" are above the rails or guides 47. Move.

  The configuration of the gears is different from that shown in the figure by offsetting the gears along the direction X, or by locally dividing the connection part in the area where the connection part 62 ″ ′ exists, etc. It may be by arranging gears.

  As an alternative to the use of this gear, a sliding runner mounted on a rack and sliding along a rail or guide may be used.

  The mandrel conveyor 6 also includes an unlocking device 61 for fitting a first tongue provided in the rear area of the mandrel used in the rolling process. The unlocking device 61 is of the so-called “draw bridge” type and acts in conjunction with the rear tongue of the mandrel 31. The closed position of the drawbridge is shown in FIGS. 6 and 7, whereas the open position is shown in FIG.

  The device 61 includes two separate heads 68 and 69 that are integrally fixed to the front ends of the rack 62 ′ and the rack 62 ″, the other end of the recess disposed in the second head 69, and the rear of the mandrel. A lever 67 hinged to the first head 68, which constitutes a so-called drawbridge that mates with the upper part of the tongue, which is an inverted U-shaped groove complementary to the shape of the rear tongue of the mandrel 67 ″ is formed in the central portion. It is also possible to arrange the elements of the device 61 so as to have the fulcrum of the lever 67 included in the head 69 having the same function as the previous modification and the reverse rotation direction.

  The unlocking device 61 has a control device 63 for controlling the rapid opening and closing of the lever 67 in each rolling cycle. On the other hand, the control device 63 is controlled by the movable cam 65 or an equivalent operation device. The control device 63 is attached to the head 68. The control device 63 is composed of a kinematic chain mechanism having a support pin 45 of a lever 67 hinged to the head 68 itself, respective supports, and a conical gear for transmitting rotational motion at 90 °. The In addition, a shaft and control lever 63 ', preferably provided with gears, the necessary support of the shaft and a bistable system 89, preferably of the extended rod type with springs, are provided. The bistable system 89 maintains the control lever 63 'in two alternating lowered and raised positions corresponding to the two positions of the fixed and non-fixed mandrels. As shown in FIGS. 6 to 8, the lever 67 moves from the locking position to the release position by rotating counterclockwise. On the other hand, it shifts from the release position to the locking position by the clockwise rotation.

  There is a locking device 64 of the lever 67 in the closed position, which may be controlled by the respective movable cam device 66 or other equivalent actuating device. The lock device 64 at the lowered position of the lever 67 is included in the head 69. The locking device 64 includes a fixing pin 46 of a lever 67 integral with the head 69, respective supports, a conical gear for 90 ° transmission of movement, a shaft preferably having a gear, and a control lever 64 ′. And a kinematic chain mechanism with the necessary shaft support. The fixing pin 46 fits into a suitably shaped recess 67 ′ provided in the lever 67. The control device 64 is preferably rotated to act on the pin 46, so that the pin 46 rotates from the release position from the respective molding recess 67 'to the blocking position with the molding recess 67'. This locking device 64 is included in a head 68, suitable for maintaining the control lever 64 'in two alternating positions corresponding to the locking of the lowered drawbridge 67 and the release of the drawbridge 67 rotating the drawbridge to the open position. Including the use of a bistable system 89 'similar to the system 89 described.

  Two cams 65, 66 or actuating devices which are arranged at predetermined positions along the rolling line and are fixed in the sliding direction of the racks 62 ', 62 "are connected to the respective control levers 63', 64 'by an unlocking device. When 61 reaches, a vertical motion corresponding to the angular displacement of these control levers can be generated.

  At least two cams 65, 66 or actuators are mounted at each of the points where the rear tongue of the mandrel 31 is to be locked and unlocked. If the rolling plant R also includes an emergency guillotine 9, another device 65, 66 may be provided to release the mandrel at the emergency position.

  This advantageous configuration of the mandrel transfer device 6 makes it possible to simplify a mandrel support device constituted by a roll having a vertically movable shaft, one of which is schematically indicated by the numeral 92 in the figure. In fact, during the movement of the locking device 61, the roll can pass through the space provided between the two heads 68 and 69, so the roll 92 is lowered to a space equal to the height of the installation range of the heads 68 and 69. There is no need.

  The mandrel conveyor 7 on the outlet side 22 in the first embodiment has a mandrel support device composed of rolls of adjustable height and a known type of mandrel longitudinal actuation system not shown in FIG. The conveyor 7 further includes a rack 72 and drawbridge unlocking device 71 similar to those described above, illustrated in more detail in FIGS. The rack 72 includes two balanced teeth 78 and 78 ′ disposed above and below the rolling axis X. The rack includes gears 84 and 84 'for facilitating axial sliding. Instead of using a gear for the rack 72, a sliding runner that is integral with the rack 72 and slides on a rail or a guide may be used.

  The second tongue or front tongue of the mandrel disposed near the head end of the mandrel 31 itself is fitted by the device 71. The locking position of the device 71 is shown in FIGS. 13 and 14, whereas the release position of the mandrel of the device is shown in FIG.

  The apparatus 71 also has a head 76 fixed to the front end of the rack 72 on the outlet side of the rolling mill, and a lever 77 (exactly a draw bridge) hinged to the head 76. The head 76 also includes the presence of a gear 79 that moves on the rail 48. The unlocking device 71 is engaged with the lower part which is a lever 77 having an inverted U-shaped groove 77 ′ which is complementary to the groove of the front tongue of the mandrel 31 by fitting the mandrel only with the upper part of the tongue. It is designed not to match. As can be seen from the drawing, the device 71 may shift from the locking position of the mandrel 31 to the releasing position by rotating counterclockwise about the axis of the pin 87. In contrast, the mandrel 31 is shifted from the released position to the locked position by the clockwise rotation.

  It can be mentioned that the two views shown in FIGS. 9 and 10 are arranged opposite to FIGS. 2 and 3 for the part 62 described above, as can be inferred from the arrangement of the arrows 23 indicating the rolling direction.

    It is also possible to arrange the head 76 on the opposite side with respect to the rolling axis X. In this case, the same function can be obtained by rotating the lever in the opposite direction.

  The device 71 is integral with the rack and has an opening / closing control device 73 for a lever 77 included in a head 76 controlled by a movable cam 75 or an equivalent operation device.

  The control device 73 is a kinematic chain mechanism having a support pin with respective supports, a conical gear for 90 ° transmission of movement, preferably a shaft with gears, a control lever 73 ′, and a bistable system 88. Configure. The bistable system 88 is preferably of the elongate rod type that maintains the control lever 73 ′ in two alternating positions corresponding to the closed drawbridge 77 and the open drawbridge 77 and comprises a spring.

  The movable cam 75 is suitable for fitting with a control lever 73 ′ fixed in the sliding direction of the rack 72, and when the unlocking device 71 reaches each control lever 73 ′, the movable cam 75 is moved in the vertical direction. It is possible to induce angular displacement. At least two movable cams 75 are provided in the rolling plant and are mounted at the unlocking position of the front tongue portion of the mandrel 31.

  A further variant of the outlet area mandrel transfer device 7 is shown in FIGS. 9a and 18-22. The same number is attached | subjected to the same component as the modification mentioned above.

  In this variant, the mandrel lock release device 71, denoted here by the numeral 71 'and having the lever 97, prevents the pipe from coming off laterally with respect to the rolling axis X when the lever is in the lowered position. It is formed so that it can be provided with tube enclosure walls 90 ', 90 "on the sides of the conveyor 7 used in the process. As shown in Fig. 9a, the walls 90', 90" have their length. Is cut off to allow passage through the tube removal device and the mandrel loading device. In this case, the axis X1 of the rack 72 is preferably arranged in the vertical direction at the raised position with respect to the rolling axis X.

  Reference to the device 71 shown below can also be applied to the variant 71 ′.

  The speed control system of the rack 72 and the mandrel unlocking device 71 has an automated pinion box 81. The pinion box 81 comprises a shaft support structure having two gears 83, 83 'when mounted above and below the teeth 78, 78' of the rack 72 to be fitted to transmit the necessary force and motion. The The driving device 80 also includes one or more speed reducers and a number of motors corresponding to the number of gears of the pinion box. The motor and the shaft coming out of the pinion box 81 are all preferably arranged on the same side with respect to the rolling axis. The unlocking devices 61 and 71 on the inlet side 20 and the outlet side 22 included in the respective conveyors 6 and 7 are arranged so that mandrel locking and unlocking operations that operate in a given rolling cycle at each end and end are performed in each cycle. The control is performed in a reciprocating manner so as to be executed periodically and rapidly.

  In the rolling mill 5, the mandrel itself moves in the direction opposite to the rolling direction 23 through the rolling stand 12 and possibly the rounding stand 10 in the absence of a tube, and the roll collides with the roll. In order to prevent the mandrel from being damaged, a mandrel support stand 8 that functions to hold the mandrel 31 in the centering state is provided. The mandrel support stand 8 is a prior art device that consists of an adjustable roll that closes and opens quickly to the size of the mandrel and allows the perforated shell to pass through to the rolling stage.

  The rolling plant R further improves the rolling process and advantageously, but not necessarily, includes several devices that may all be present together or inserted individually. A guillotine-like stop device 9, also referred to as an emergency guillotine, is provided on the inlet side 20 along the rolling axis X, which is suitable for being activated in order to withdraw the mandrel from the tube in case of an emergency. The emergency guillotine 9 has a retractable U-shaped resting surface that is movable between a non-interfering position and an interfering position that includes the end section of the perforated shell. Such a surface is used to contrast the movement of the drilling shell or tube if the rolling is interrupted while the drilling shell or tube being rolled is still inserted into the mandrel. The emergency guillotine 9 is always arranged at various points on the inlet side 20 on the rolling axis X in all cases. A preferred solution is to place the emergency guillotine 9 on the inlet side 20 and align it in the inlet area 20 with the tip of the mandrel when in the retracted position and locked in the unlocking device 61 in the emergency withdrawal position Leaving a space between the trailing edge of the perforated shell when done.

  A rounding stand 10 can be provided which is arranged downstream of the final rolling mill 12 for rolling the thickness. The purpose of the rounding stand 10 is to create a substantially uniform gap between the mandrel and the inner diameter of the tube and may be used as an effective device for braking the tube at the end of the rolling cycle. When the end of the rolled tube leaves the final stand that reduces the thickness, the tube itself may be braked using a rounding stand. Such an operation can reduce the cycle time and space required to brake the tube itself at the end of rolling. Alternatively, a plurality of rounding stands 10 arranged in order along the rolling axis X can be provided.

  A feeder 11 for a perforated shell to the rolling mill may be provided in the rolling plant R. For the sake of simplicity, the feeding device 11 shown only in FIG. 4 has at least one motorized and the drilling shell from the opposite position to the drilling shell which is not subject to any obstruction after the drilling shell is loaded on the rolling axis X. It is preferred to have one or more series of balancing rolls that move to a single location for contact. Such a feeding device 11 can feed the perforated shell to the multi-stand rolling mill 5 under speed and position control conditions.

  Furthermore, it is convenient, but not essential, that the feeder device 11 is used to hold the perforated shell in place during the backward insertion step of the mandrel into the perforated shell.

  The above-described rolling plant R according to the invention can carry out a particularly advantageous high-productivity pipe rolling process in an optimal manner. The stages of this type of rolling process are described in detail below. Conventionally, unless otherwise specified, the “front” and “rear” notation of the various elements refers to the rolling direction 23, that is, the front refers to the tip of the arrow and the rear refers to the end of the arrow 23.

  In FIG. 1, the rolling plant R is shown with the parts arranged at a particular rolling stage of the pipe in some rolling process cycle. To generalize the description, “n” refers to the above cycle, and “n” is an ordinal number that refers to a typical full rate maximum speed rolling cycle.

  At the start of the cycle “n”, the mandrel 31 ready to be inserted on the rolling line X is arranged on the outlet side 22 to the side of the rolling line X by starting the rotary arm 4 in the lateral direction. . The mandrel locking device 71 on the outlet side 22 is arranged along the rolling line at the height of the tip of the mandrel 31 at the locking position P1.

  By activating the rotary arm 1 by translation that is transverse to the axis X, the piercing shell 39 is placed in the rolling line X with the front end of the piercing shell 39 in the feeder 11.

  The locking device 61 moves to the rear end of the perforated shell 39 in the direction of the arrow 23 and takes the locking position of the mandrel 31. At the same time and in a harmonious manner, the mandrel 31 is loaded along the rolling axis X by the rotation of the rotating arm 4 by performing the operation on the outlet side 22, and the front tongue of the mandrel 31 is attached to the locking device 71. Once gripped, the locking device starts a translational movement that presses the mandrel together in the direction opposite to the rolling direction 23.

  Subsequently, the mandrel 31 pressed by the locking device 71 is first moved from the inside of the multi-stand rolling mill 5 to the rear, which is opposite to the rolling direction, and guided by the mandrel support stand 8 in such an operation. Thus, until the rear area of the mandrel 31 comes out of the rear area of the perforated shell 39, it passes through the inside of the shaft hole of the perforated shell 39 and is arranged in the locking device 61. When the mandrel 31 reaches this position, the locking device 71 releases the locking of the front tongue portion of the mandrel 31. At the same time and in an adjusting manner, the locking device 61 grips the rear tongue of the mandrel 31. In this manner, the front end portion of the perforated shell 39 is gripped by the feeding device 11 that pulls the perforated shell inside the multi-stand rolling mill 5, and the rolling step shown in FIG. 1 is executed.

  The rolling of the perforated shell 39 inside the multi-stand rolling mill 5 is performed in a state in which the mandrel 31 is pulled by the locking device 61 by the operation in the direction of the arrow L3 that is the reverse of the arrow 23. The movement of the mandrel 31 is adjusted in accordance with the movement of the tube 42 indicated by the arrow L4 generated by the roll of the rolling stand 12 of the rolling mill 5. The speed of movement of the mandrel 31 in the direction of the arrow L3 is indicated by reference numeral 12 in FIG. 1 where the front end of the mandrel 31 is at the rear end of the tube 42 and defines the final rolling stand 12, or “contact point”. It is set so that it is completely rolled when the rear end of the tube comes out of the rightmost stand. In this way, the mandrel 31 is completely withdrawn from the fully rolled cavity of the tube 42 after passing the abutment point.

  Here, the locking device 71 released from the mandrel 31 moves for a while to the locking position P1 by the movement indicated by the arrow L5 coinciding with the rolling direction 23, where the next rolling cycle “n + 1” is performed. Another mandrel (not shown) used in is locked.

  As shown in FIG. 1, the tube 42 may pass through one or more rounding stands 10 in addition to being rolled by the rolls of the rolling stand 12. This operation is optional and contributes to improving the shape of the finished tube.

  In this final rolling stage, before starting the next rolling cycle “n + 1”, the mandrel 31 that has left the inside of the pipe 42 is braked because it is discharged from the rolling line in the lateral direction by the rotation of the rotary arm 2. , And arranged on the rolling axis X at a position away from the multi-stand rolling mill 5.

  With the adjustment method, when the rear tongue portion of the mandrel 31 is in the release position P3, the engagement of the locking device 61 is released, and the rotation of the rotary arm 2 in the lateral direction enables discharge from the rolling axis X. To do.

  Thus, the next drilling shell rolling cycle “n + 1” may be started using the next mandrel, in the same operation as the previous cycle “n” described above.

Claims (13)

A mandrel transfer device (6) for a multi-stand tube mill with a mandrel defining a rolling axis (X),
A rack device (62) and an unlocking device (61) for locking and releasing the tongue of the mandrel (31),
The rack device (62) has two racks (62 ′, 62 ″) arranged in parallel with the rolling axis (X),
The two racks each have two teeth ((51, 51 ′), (52, 52 ′)), and the unlocking device (61) is disposed at one end of the two racks. apparatus.   The device according to claim 1, wherein the unlocking device (61) has two heads (68, 69) arranged at one end of each rack (62 ', 62 ").   3. The device according to claim 2, wherein the two racks (62 ', 62 ") are coupled along a part of their length by a coupling element (62").   4. The apparatus according to claim 3, wherein the two teeth of each rack are symmetrically arranged one above and below the rolling axis (X).   The locking release device (61) has a lever (67) suitable for moving by an angular swing between the locking position of the tongue of the mandrel (31) and the releasing position; The apparatus according to claim 4, wherein the angular swing is performed in a plane intersecting the rolling axis (X).   6. A device according to claim 5, comprising a cam device (65), the unlocking device (61) comprising a mechanism (63) operated by the cam device (65).   The device according to claim 6, wherein the unlocking device (61) comprises a blocking device that blocks the lever (67) in the locking position of the mandrel. A rolling plant (R) for a pipe having a specified length,
A rolling mill (5) having a plurality of rolling stands (12) for rolling the perforated shell (39) to transform the shell into a rolled tube, and defining a rolling axis (X);
At least one mandrel (31) having a front end and a rear end and cooperating with the rolling mill (5) during the rolling;
Have
The rolling plant (R) is upstream of the rolling mill (5),
A first loading device (1) for loading the perforated shell (39) along the rolling axis (X);
A first take-out device (2) for taking out the at least one mandrel (31) from the rolling shaft (X);
A first transfer device (6) according to any one of claims 1 to 7,
The rolling plant (R) is downstream of the rolling mill (5),
A second take-out device (3) for taking out the rolled tube from the rolling shaft (X);
A second loading device (4) for loading at least one of the mandrels (31) along the rolling axis (X);
A second transfer device (7) having a second unlocking device (71, 71 ') for locking and releasing the front end of at least one mandrel (31);
Having a rolling plant.   In each rolling cycle, the rolling plant that harmonizes the first transfer device (6) and the second transfer device (7) by locking and releasing the front and rear ends of at least one mandrel (31) ( 9. The rolling plant according to claim 8, wherein a control means R) is provided.   The front end portion and the rear end portion of at least one of the mandrels (31) respectively include a front tongue portion and a rear tongue portion for performing the unlocking operation by the first transfer device and the second transfer device. The rolling plant according to claim 9.   11. A rolling plant according to claim 10, wherein the rolling mill (5) has a mandrel support stand (8).   The rolling plant according to claim 11, wherein a feed device (11) for the perforation bar (39) is provided in the rolling mill (5). 13. A rolling plant according to claim 12, wherein at least one rounding stand (10) is provided downstream of the final rolling stand of the rolling mill (5).

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